Electrically operated jack-like actuators



June-23, 1959 T. w. MlLLNS 2,891,413

ELECTRICALLY OPERATED JACK-LIKE ACTUATORS Filed May ;3, 1957 UnitedStates Patent ELECTRICALLY OPERATED JACK-LIKE ACTUATORS Terence WilliamMillns, Westway, Shepherds Bush, London, England, assignor to RotaxLimited, W1llesden, London, England Application May 13, 1957, Serial No.658,715

2 Claims. (Cl. 74-4243) This invention relates to electrically operatedjack-like actuators for moving the flight control members of aircraft orfor other purposes and of the type comprising a pair of hollowcylindrical telescopic members one of which is in screw-threadconnection with the other member.

The object of the invention is to enable an actuator of the said type tobe provided in a compact form.

An actuator in accordance with the invention comprises a construction inwhich the electric motor and associated speed reduction gear areaccommodated within the rotatable member of the actuator.

In one example, as illustrated by the accompanying drawing, the actuatorcomprises a hollow cylindrical housing a which is closed at one end byan end cover b. From the inner face of the cover extends an axiallyarranged sub-housing c which contains the electric driving motor d andspeed reduction gearing e of the epicyclic or other type. The poweroutput shaft driven by the gearing extends through the inner end of thesub-housing and has secured to it a disc g to the periphery of which issecured a hollow cylindrical jack member h having a helical groove iformed along its outer surface. The subhousing containing the motor andgearing lies within one end of the said jack member.

Around the rotary jack member h is arranged the hollow cylindrical andaxially movable complementary jack member k. At one end this member isengaged with a longitudinal groove m in the inner surface of the outerhousing a the connection being conveniently formed by a series of ballsit carried by one end of the jack member k. Also one end of the member kis adapted to form a nut for engaging the helical groove of the rotaryjack member 11. Preferably the nut consists in part of an annulararrangement of balls 0 engaging the helical groove of the rotary memberh and carried in a groove in the other member k.

The axially movable member k is supported in part 2,891,413 PatentedJune 23, 1959 ICC by the inner surface of the outer housing and by agland p combined with the end of the housing through which the outer endof the said member k extends, the said end being closed by a cover q.

From the foregoing it will be understood that the whole of the motor andits associated gearing lies wholly within the rotary jack member 0. Bythis arrangement an actuator is provided in a form which is more compactso far as the overall length of the apparatus is concerned than anactuator of the same type and of conventional construction.

Having thus described my invention What I claim as new and desire tosecure by Letters Patent is:

1. An electrically operated jack-like actuator comprising in combinationa pair of inner and outer hollow cylindrical telescopic members, theinner of which is rotatable but axially immovable, and the outer ofwhich is axially movable but non-rotatable, means interconnecting saidinner and outer members so that rotation of the inner member isaccompanied by axial movement of the outer member, an electric actuatingmotor accommodated within the rotatable member, and speed reductiongearing through the medium of which said motor is operatively connectedto said rotatable member, and which is also accommodated within saidrotatable member.

2. An electrically operated jack-like actuator according to claim 3, andhaving in combination a hollow cylindrical housing in which therotatable inner member and axially movable outer member are mounted,means effecting a slidable but non-rotatable connection between saidaxially movable member and said housing, a cover closing one end of saidhousing, an axially arranged subhousing extending from said cover intosaid rotatable member, and containing the electric actuating motor andspeed reduction gearing, and an output shaft extending through the endof said sub-housing remote from said cover, and having a drivingconnection at one end with said gearing, the other end of said shaftbeing connected to said rotatable member.

References Cited in the file of this patent UNITED STATES PATENTS1,878,219 Wiard Sept. 20, 1932 2,260,671 Humphrey Oct. 28, 19412,438,545 Davidson Mar. 30, 1948 2,482,568 Werner Sept. 20, 19492,639,625 Geyer et al. May 26, 1953 2,751,789 Orenick June 26, 1956FOREIGN PATENTS 220,914 Switzerland Apr. 30, 1942

